diff --git a/README.md b/README.md
index 540279f..90afe66 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ Adds support for fulltext search engines like Sphinx and Solr to SilverStripe CM
 
 ## Requirements
 
-* SilverStripe 3.0
+* SilverStripe 3.1+
 * (optional) [silverstripe-phockito](https://github.com/hafriedlander/silverstripe-phockito) (for testing)
 
 ## Documentation
diff --git a/code/search/SearchIntrospection.php b/code/search/SearchIntrospection.php
index 2847b1f..bcebe40 100644
--- a/code/search/SearchIntrospection.php
+++ b/code/search/SearchIntrospection.php
@@ -70,9 +70,9 @@ class SearchIntrospection {
 	 */
 	static function has_extension($class, $extension, $includeSubclasses = true) {
 		foreach (self::hierarchy($class, $includeSubclasses) as $relatedclass) {
-			if (Object::has_extension($relatedclass, $extension)) return true;
+			if ($relatedclass::has_extension($extension)) return true;
 		}
 		return false;
 	}
 
-}
\ No newline at end of file
+}
diff --git a/composer.json b/composer.json
index 97ec09d..372663d 100644
--- a/composer.json
+++ b/composer.json
@@ -11,6 +11,6 @@
 	],
 	"require":
 	{
-		"silverstripe/framework": "3.*"
+		"silverstripe/framework": "3.1.*"
 	}
 }